The present invention relates to a space-saving selector for equiping radiological apparatus.
The different radiological stands, and more especially conventional stands with remote-controlled tables, comprise a selector. This latter, located in the examination table under the patient-carrying panel, is meant to receive a cassette containing a radiographic film for providing radiograms of the desired format. Generally, for this purpose, the cassette moves in the selector under an adjustable masking device, such for example as mobile masking flaps: the movements of said cassette and masking flaps are controlled by electro-mechanical or electronic means which this selector comprises, so as to cause the cassette to occupy a position in which the exposed radiographic film surface corresponds to the desired format.
A radioscopic examination is frequently carried out before the virtual radiological image is fixed on the radiographic film and a radiation detector such as a luminance amplifier is then used. This latter, as well as the selector, is able to move inside the examination table along an axis parallel to the longitudinal axis thereof and, by means of a servo-control device, the position of the selector may be centered on that of the luminance amplifier. Thus, after the radioscopic examination, the radiography may be undertaken with a minimum loss of time, since the selector is already in the proper position: of course, during the radioscopy, the path must be freed for the radiation beam, more especially by moving aside the masking flaps and the cassette.
So, there exist selectors in which the radiographic cassette, during the radioscopy sequence, is sheltered from the X-rays in a waiting position, in an additional space which this selector comprises; but this requires a larger dimension of this latter which must then comprise at least one surface double that of the radiographic cassette. This dimensional increase of the selector is provided either along the longitudinal axis of the examination table or along the transverse axis thereof.
The disadvantages thereof are the following: in so far as the increase in the dimension of the selector along a longitudinal axis of the examination table is concerned; the disadvantage consists in that the active part of the selector, i.e. that in which the radiographic film is sensitized by the X-rays, cannot be brought up to one of the ends of the examination table, because of the room required for this additional space. This defect is important, in that in some cases an examination cannot be readily accomplished and may require the patient to be moved. In the case where the dimensional increase of the selector is along an axis transversal to the examination table; the above-mentioned disadvantage no longer exists; on the other hand this dimensional increase of the selector leads to increasing to the same extent the width of the examination table.